This invention relates to vacuum cleaners and, more particularly, to an improved arrangement for controlling the suction at the nozzle of a canister vacuum cleaner.
Canister vacuum cleaners typically include a chassis member, supported on a floor surface by means of wheels or runners, which includes therein a motor/blower unit for producing suction at an inlet port. A flexible hose has a first end connected to the inlet port and a second end connected to a rigid handle section. At the other end of the handle section, there is connected an elongated wand which has a floor cleaning nozzle connected to the end remote from the handle section. The wand and floor cleaning nozzle can be replaced by other tools, such as for example, a crevice tool, an upholstery nozzle, or a drapery cleaning nozzle.
It is often desirable to be able to control the amount of suction at the nozzle, depending upon the cleaning operation being performed. One way of controlling the suction is to control the speed of the motor producing the suction. However, to provide an arrangement whereby the operator controls the speed of the motor results in increased complexity and resultant cost of the vacuum cleaner. Accordingly, it has become common for vacuum cleaner manufacturers to provide a bleed hole in the handle section along with a movable cover partially encircling the handle section which the operator can rotate to expose all, part or none of the bleed hole so as to selectively divert suction from the nozzle. This is a far less costly approach than controlling the speed of the motor. However, an opening in a wall surrounding a fast moving air stream, as above described, produces noise which is an irritant to the vacuum cleaner operator.
Accordingly, it is a primary object of this invention to provide an arrangement for controlling the suction at the nozzle of a canister vacuum cleaner without the attendant noise irritant.